Temperature-Gradient Induced Mass-Instability Theory of Glacier Surge

• Published in: Journal of Glaciology
• Main Author: Shoemaker, E. M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1976
• Subjects: Earth-Surface Processes; Journal of Glaciology
• Online Access: http://dx.doi.org/10.1017/s0022143000013721; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000013721

A theory is proposed that glacier surges are the result of a time-independent but positionally-dependent temperature distribution in which the mean effective temperature increases down slope. The theory is modeled by a slab analogy in which plane motion on a plane slope consists of uniform shear in a sub-region called the reservoir region. Assuming the usual power function relationship between stress and strain-rate, a thickening of the glacier in excess of its constant-state condition tends to induce instability; i.e. as the reservoir region thickens the oscillation of the region (up and down the slope) becomes unstable. Assuming an accumulation rate which increases linearly with elevation, this oscillation is represented by a non-linear ordinary differential equation. Numerical results are considered and reasonable assumptions, where data does not exist, render surge cycle times in close agreement with observation. The theory does not require basal sliding but this can be included.